I have killed them with a custom 45 ACP with 185g speer gold dots with a load of 9.6g of AA#5, and a Ruger GP 100 with Sierra 125g HP loaded with 17.8g of IMR 4227. I replaced the sights on the ruger to a V notch rear sight and a beade front sight, you could really get a fine hold, and along with a super light trigger made for super accurate pistol. The 357 killed quicker than the 45, except on Javelina.
I was hunting in Az at the time, thickish places were shots were within 50 yards. I had several coyotes pick me up due to the glare on the SS finish, Wal Mart camo duct tape fixed that.
I sat on a small fold up stool, back into a carved out section of a bush, pistol in hand, safety off on the 45 ready to fire, or hammer cocked back on the 357. I have had them fleer from the safety being clicked off on the 45 and the hammer being cocked on the 357....this will really piss you off when it happens. Both of these pistols had around a 2 lb single action trigger pull.
Filled my Javelina tag every year with one of the above pistols using a coarse sounding hand call, Weems Duo Tone.
Hunting coyotes with a scoped pistol, eh, well....that is a tough sport. More often than not, they are moving when you take the shot.